Aug 17, 2020
This week’s episode of Circulation on the Run features author Ami Aronheim and Associate Editor Thomas Eschenhagen as they discuss early cardiac remodeling that promotes tumor growth and metastasis.
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, associate editor of the National Heart Center and Duke National University of Singapore.
Dr Greg Hundley: And I'm Dr Greg Hundley, associate editor and director of the Pauley Heart Center at VCU Health in Richmond, Virginia.
Dr Carolyn Lam: Greg, today we're taking a look at the cardio-oncology world in our feature discussion, but in a very interesting reverse way. Cardio-oncology, what would you think of? I suppose the effects on the heart of cardiotoxic drugs that we use in oncology, right? But this feature paper looks at it the other way around and says does the heart and its remodeling promote tumor growth and cancer? Terribly interesting data coming right up after we discuss a couple of papers, well, all the papers in today's issue.
So I want to start. Greg, do you remember what parasites are and why they're important?
Dr Greg Hundley: Well, Carolyn, this is actually one of the things that I do remember because we study the parasites when we're looking at microcirculatory dysfunction after the administration of potentially cardiotoxic agents for treatment of cancer. But how about you tell us a little bit more.
Dr Carolyn Lam: This is going to be very basic just for all of us. Now, the blood vessels are composed of endothelial cells and mural cells. Endothelial cells line the vascular lumen. Whereas the mural cells, which include faster smooth muscle cells and parasites adhere to the abluminal surface of the endothelium. Parasites regulate vessels stabilization and function, and their loss has been associated in diseases such as diabetic retinopathy, vascular malformation, stroke, and cancer. Just like you said, Greg.
Now here we have a series of elegant experiments by Dr Mariona Graupera from IDIBELL in Barcelona and colleagues who use genetic mouse models to identify the specific molecular signature of mural cells at early and late stages of the energetic process and unveil their biological relevance. Their results show that phosphatidyl inositol 3-kinase or PI3K-beta is the main regulator of parasite, proliferation and maturation in vessel growth. PI3K-beta deletion in parasites triggered early parasite maturation, whereas exacerbated PI3K signaling delayed parasite maturation, and thus vessel maturation during angiogenesis.
Dr Greg Hundley: So clinically what's the take home message here.
Dr Carolyn Lam: The proposed model of mural cell maturation together with the tools developed would be instrumental for the characterization of mural cells in pathologies associated with deregulated vessel growth, such as ischemia stroke, vascular malformation, diabetic retinopathy, and cancer. The therapeutic potential of modulating parasite biology through PI3K signaling provides a new window of clinical intervention for vascular related diseases in which parasite dysfunction contributes to their onset and or progression.
Dr Greg Hundley: Very nice, a very important cell type Carolyn. Well, my paper comes from Professor Xiang Qian Lao from The Chinese University of Hong Kong. In this paper, the authors investigated in 140,072 adults all greater than the age of 18, without hypertension who joined a standard medical screening program with 360,905 medical exams that occurred between the years of 2001 and 2016. They assess the joint associations of habitual physical activity and long-term exposure to find particulate matter with the development of hypertension in Taiwan.
Dr Carolyn Lam: Wow. A huge study. So what did they find Greg?
Dr Greg Hundley: After adjusting for a wide range of co-variants including a mutual adjustment for physical activity or particulate matter, a higher physical activity level was associated with a lower risk of hypertension. Whereas a higher level of particulate matter was associated with a higher risk of hypertension. No significant interaction was observed between physical activity and particulate matter.
So Carolyn in conclusion, a high physical activity and a low particulate matter exposure were associated with a lower risk of hypertension. What we would expect the negative association between physical activity and hypertension remain stable in people exposed to various levels of particulate matter. The positive association between particulate matter and hypertension was not modified by physical activity. Thus, Carolyn the authors believed their results indicate that physical activity is a suitable hypertension prevention strategy for people residing in relatively polluted regions.
Dr Carolyn Lam: Oh, thanks for summarizing that. So well, Greg, Hey, I've got a question for you. Do you measure a high density, lipoprotein cholesterol or HDL cholesterol? Do you measure the levels or do you measure the particle concentration in your clinical practice?
Dr Greg Hundley: I think just the levels Carolyn.
Dr Carolyn Lam: Yeah. Same, but there's a lot of data coming out about the particle concentration. Let's review a little bit about that. So the HDL cholesterol is an established athero-protective marker, particularly for coronary artery disease, but HDL particle concentration may better predict the risk. However, the associations of HDL cholesterol and HDL particle concentration with ischemic stroke and with myocardial infarction among women and blacks has not been well defined. And so Dr Rohatgi from UT Southwestern and colleagues analyzed individual level participant data in a pool cohort of four large population studies without baseline atherosclerotic cardiovascular disease. These were the Dallas Heart Study, the ERIC study and the MISA study, as well as the PREVENT study.
Dr Greg Hundley: What did they find? Were there any unique pieces of data related to either sex or those of black race?
Dr Carolyn Lam: They found that HDL particle concentration is inversely associated with the specific endpoint of ischemic stroke overall and among women. Whereas HDL cholesterol was not associated with ischemic stroke. Neither HDL particle concentration nor HDL cholesterol levels were associated with myocardial infarction in blacks. Thus HDL particle concentration, but not HDL cholesterol may be a useful risk marker for ischemic stroke. HDL particle concentration may be a useful risk marker for both myocardial infarction and ischemic stroke among women. There is likely minimal utility of HDL markers for risk prediction of myocardial infarction in the black population.
Dr Greg Hundley: Thanks Carolyn. That was such a great introduction and overview and then the results was so clear. Carolyn, my next paper comes from Dr Peter Willeit from the Medical University of Innsbrook. In this paper, the author systematically collated carotid intima-medial thickness data from randomized controlled trials. The primary outcome was a combined cardiovascular disease endpoint defined as myocardial infarction, stroke, revascularization procedures, or a fatal cardiovascular event. The authors estimated intervention effects on carotid intima-medial thickness progression and incident CVD for each trial before relating the two using a Bayesian eta- regression approach.
Dr Carolyn Lam: Oh, this is important. So what did they find?
Dr Greg Hundley: Carolyn, they're going to have 10 micrometer per year evaluations. So across all intervention, each 10 micrometer per year reduction of carotid intima-medial thickness progression resulted in a relative risk for cardiovascular disease of 0.91 with an additional relative risk for cardiovascular disease of 0.92 being achieved independent of carotid intima-medial thickness progression. So combining these results, the authors estimate that interventions reducing carotid intima-medial thickness progression by 10, 20, 30 or 40 micrometers per year would yield relative risks of 0.84, 0.76, 0.69 or 0.63 each incrementing with the magnitude of reduction in micrometers per year. Results were similar when grouping trials by type of intervention. Time of conduct, time to ultrasound follow-up, availability of individual participant data, primary versus secondary prevention trials, the type of carotid intima-medial thickness measurement, and the proportion of women in the studies.
Dr Carolyn Lam: So could you summarize that Greg?
Dr Greg Hundley: You bet, Carolyn. So the extent of intervention effects on carotid intimal-medial thickness progression predicted the degree of cardiovascular disease risk reduction. This provides a missing link supporting the usefulness of carotid intimal-medial thickness progression as a surrogate marker for cardiovascular disease risk prediction in clinical trials.
Dr Carolyn Lam: Indeed. Thanks, Greg. It's important because it also quantifies that risk reduction. Very nice. Now let's just round up with some other papers in the issue. There is a perspective paper by Dr Bunch on Dementia and atrial fibrillation, a research letter by Dr Ellinor on myocyte specific upregulation of ACE two in cardiovascular disease, the implications for our SARS-coronavirus to mediated myocarditis. There are letters to the editor regarding the article small extra cellular macrovesicles mediated, pathological communications between dysfunctional adipocytes and cardiomyocytes as a novel mechanism, exacerbating ischemia reperfusion injury in diabetic mice. These letters were by Dr Li with response by Dr Ma. There's a research letter by Dr Natarajan on genetic variation and cardiometabolic traits and medication targets and the risk of hypertensive disorders of pregnancy.
Dr Greg Hundley: Carolyn, I've got a couple other features to describe. Aaron Baggish and Ben Levine provide an On My Mind piece, related to sports after COVID-19. Jeffrey Smietana has an ECG challenge regarding an ELVAD artifact. Then finally, Bridget Kuhn has cardiology news related to an announcement from the Association of Black Cardiologists calling for an urgent effort to address health inequality and diversity in cardiology. Can't wait to get to that feature discussion and that really unique twist in cardio-oncology.
Dr Carolyn Lam: Here we go. Greg.
Based feature discussion. We are diving into the world of cardio-oncology. Now, usually that refers to the intersection between cancer and cardiovascular disease, where we usually talk about cancer and cancer treatment effects on the cardiovascular system. But emerging data now suggests the concept of reverse cardio-oncology, whereby heart disease potentiates cancer. Today's feature paper really provides very important and significant preclinical data to support this. I'm so pleased to have with us, the corresponding author, Dr Ami Aronheim from Israel Institute of Technology, as well as our associate editor, Dr Thomas Eschenhagen from University Hospital Hamburg Eppendorf in Germany. Ami, thank you very much for joining us today. Please. Could you walk us through your very elegance study and the results?
Prof Ami Aronheim: We used a model, which is called the transfers, all the constriction, which promotes pressure overload on the heart. Actually following this procedure, we implanted cancer cells into mice and we followed the growth of these tumors. Actually we found out that the tumors of a tuck operated mice is growing much faster. Also when we used a metastatic model, namely, when we injected cells into the tail vein, we obtained more metastatic lesions in the lungs. Actually we found out that the serum from these mice is able to promote the variation of cancer cells in vitro. Then we also identified a protein, which is potentially promoting these cell proliferation in vitro.
Dr Carolyn Lam: That is really significant. I mean, am I right that this is the first study to show that cardiac remodeling actually promotes tumor growth and metastasis and this is probably via secreted factor.
Prof Ami Aronheim: This is the first paper showing that early events of cardiac remodeling promote cancer cell proliferation. It is known that heart failure by the work of De Boer’s group, that heart failure is promoting cancer load in mice. This paper was also published in Circulation 2018.
Dr Carolyn Lam: Indeed. Thank you for reminding me about that. And I am a huge fan of Rudolph de Boer and his work. Indeed. Could I ask though, in your study, did you identify a particular secreted factor?
Prof Ami Aronheim: We looked at the RNA seq from conduct remodeled heart, and we looked for secreted factors in the heart and we focused on two secreted factors CTGF and periostin, which are known to promote cancer growth. And indeed we found in our mice models that reduced in level is increased in the serum of mice of tuck operated mice. Once we deplete the serum from periostin, we ambulated this increase in cell proliferation.
Dr Carolyn Lam: Wow. So periostin appears a culprit, but I'm sure the listeners are dying to know. Was there any human data that you had that supported the animal findings?
Prof Ami Aronheim: The model in mice, the tack operation, it's hard to find the right model in human because the operation is really rapid. When the mice wake up, they have this pressure overload, the only disease which in human correlates or is mimicked by the tag is Altucher's stenosis, which is the restriction of the outtake evolve, the right aortic valve]. And we looked in these patients and what we found out, we looked at the echo cardiography data of a lot of patients. We actually found out that for young basically patients 40 to 60 years old, if they have moderate to severe aortic stenosis, they have higher risk to develop cancer about 1.6-fold higher than our external these patients. Although I must say with caution that this size group is quite small and it should be repeated with much higher number of patients.
Dr Carolyn Lam: Wow. Thank you so much, Ami. Thomas, I have to bring you in here. Thank you for managing this very remarkable paper. Could you share some thoughts on what you think this means for the field?
Thomas Eschenhagen: We all immediately as editorial team like this paper. When it came in on the background of the different paper, it really provides significant additional evidence that this interaction between cancer and the heart is two sided. And that's, as you said in the intro, that's really very important. And it's all very interesting that apparently these two different models used by Rudolf de Boer, which wasn't ischemia myocardial injury model. And here it's a hypertrophy model with early remodeling. They both do similar things, but apparently by different mechanisms. Because the number of the factors identified in the de Boer paper do not match with, with these two factors, CTGF and periostin. And for both, I think we have now convincing evidence that they may play a role, but it also shows that this is probably a quite complex interaction between the heart and the cancer. That makes it extremely interesting.
Of course it's important because it's such a common comorbidity, I mean, cancer, cardiovascular diseases, are the most prevalent and the second most prevalent diseases is cancer. So this interaction must be very, very important. And it's very good that these two papers now focus of you on the reverse side and not only on the classic cardiac toxicity side, which me as pharmacologists, of course, we, I was always interested in.
Dr Carolyn Lam: Yeah, indeed. I mean, Thomas me too. As a heart failure clinical trial list and epidemiologists, if I may, I always thought it was just shared risk factors, you know, age being particularly one of them.
Thomas Eschenhagen: Obviously, as you said, shared risk factors do play a role must, must their role. So it's certainly not only this direct interaction, but this new paper shows that there is in addition to this risk factor model, something specific. And that of course could be, I mean, at least theoretically be addressed.
Dr Carolyn Lam: For both Thomas and Ami, what do you think are the implications now? I mean, should we be screening all patients with aortic stenosis more closely for cancers? What do you think are the clinical implications? Maybe Ami first?
Prof Ami Aronheim: I think cardiovascular disease patients are already watched very carefully beforehand. But certainly I think that they should be also observed for cancer specifically. So yes I believe it should be. Also I this cardiovascular treatment should consider to make them early as possible to avoid any interaction with cancer.
Dr Carolyn Lam: Yeah, that completely opens the field to, for example. Early aortic valve replacement, reducing subsequent cancer risk, like you mentioned in your paper, I mean, that's just mind blowing. Thomas, what do you think?
Thomas Eschenhagen: I agree, 10 years ago, we said that more cancer patients, particularly those under treatment should be sent to the cardiologist to look for the heart. Now we will say the other way around as well. We really need to look more carefully for cancer. So I think this paper and the other one have the consequences we should do more here. There's also obviously a number of very interesting questions because one of the findings I found fascinating in this paper by Ami and this group was that this mouse strain, which finally did not show the classical science of remodeling after transverse aortic striction. So no BNP, no NP, no BDMEC increase in this small strain. There was no increase in cancer growth.
Very interesting, because normally you would think somehow that these mice, which were kind of normal in the cardiac response would be worse, but in this respect they were better. So that's a very interesting aspect. The second aspect I found really fascinating is the human data suggest, I guess it's quite preliminary data, but there's a suggestion here that this interaction is mainly seen in younger patients. And I'm not quite sure what that means, but it's something to look at.
Dr Carolyn Lam: Wow. Thanks for highlighting those Thomas. So Ami maybe the last word from you. Given all of this remaining questions and so on, what are your next steps?
Prof Ami Aronheim: First, I wanted to comment something more wide view for this interaction that we find with cancer. I think all the organs actually communicate with one another. The fact that we are looking on a heart and cancer, this is due to the fact that it's easy. We have the models working in the lab and it's easy. But I'm sure if we're going to look to other diseases and other organs, there will be other connections of the heart with other organs and other diseases and maladies, which by conducting modeling, they will promote or maybe even reverse other maladies. So I'm sure that there is a communication between all organs, many organs altogether, and they will affect one another.
Our directions currently are to look more precisely for the periostin story because we follow this mainly in vitro and would like to follow it in vivo. Also I think this mice model are nice, but to look also in human, where the periostin in aortic stenosis patients, where then, we can find out earliest in, in the serum before intervention, and to look after whether this secreted factor goes down or reduced. Also we are looking in other transgenic model that we generated along the years, which are known to result in cardiac modeling. We want to see whether these mechanisms are similar or different and whether they can promote also cancer progression. The use of these transgenic mice is very nice because we can induce them and we can shut down them so we can learn more about the kinetic, which influence one another, and exactly whether they can be reversed or not.
Dr Carolyn Lam: Thank you so much Ami for sharing your thoughts on those future actions, a lot of work and such worthwhile areas to explore. Thank you too, Thomas for sharing your thoughts.
Listeners. Thank you for joining us today on circulation on the run.
Dr Greg Hundley: This program is copyright the American Heart Association, 2020.